Watchdog control method

Abstract

The disclosed watchdog control method includes processes: (1) according to interruption time interval, the system generates interrupt, which triggers interrupt service routine; (2) reading out time variable; the time variable adds an interruption time interval when each interrupt takes place in the system; (3) comparing value of time variable with maximal time interval for feeding dog setup in system; when value of time variable is not larger than maximal time interval for feeding dog, the interrupt service routine feeds dog; when value of time variable is larger than maximal time interval, the interrupt service routine stops feeding dog, and the watchdog module resets system; (4) when application program feeds dog, the value of time variable is reset. Since maximal time interval for feeding dog can be set based on condition, longer time interval is allowed so as to prevent issue of resetting system caused by feeding dog not in time since application program for feeding dog is blocked.

Description

【Technical field】 [0001] The invention relates to a watchdog control method, in particular to a watchdog control method applied to a single-board system composed of a PCB printed circuit board, a CPU chip and other electronic devices. 【Background technique】 [0002] In single-board circuit design, it is often necessary to use a watchdog to monitor the operation of the application program and improve the reliability of the system. The maximum feeding interval T of commonly used watchdog chips is relatively short and cannot be fixed. Taking the commonly used watchdog chip ADM706 / MAX706 as an example, the maximum feeding interval T is about 1.6 seconds, so it is normal in the application program. When working, the dog feeding task of the application must ensure that the dog is fed once within 1.6 seconds, otherwise the CPU will be reset. For simple single-board systems, the dog feeding task ensures that the dog is fed in a very short time due to the simplicity of the applicati...

AI Technical Summary

Problems solved by technology

When a task writes to FLASH, sometimes it will block other tasks (including the dog feeding task) for more than 10 seconds; 3) When the CPU load is heavy, the dog feeding task cannot be scheduled within 1.6 seconds

In the above three cases, because the maximum feeding interval of commonly used watchdog chips such as ADM706 is too short, sometimes the dog feeding task cannot be guaranteed to feed the dog in time, which will cause the system to reset when the program is running normally, losing the meaning of the watchdog

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